Sierra Circuits Highlights Expertise in Castellated Hole PCB Design and Manufacturing

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Sierra Circuits brings extensive experience in designing and manufacturing PCBs with castellated holes, supporting customers who require robust, space-efficient module integration. As electronic products continue to move toward compact, modular designs, castellated holes, also known as plated half-holes, have become a critical PCB feature for reliable board-to-board interconnection.

Castellated holes are essentially plated through-holes positioned along the edge of a PCB, with their centers aligned to the board outline. This results in half-holes that allow a PCB module, such as a Wi-Fi, Bluetooth, or RF module, to be surface-mounted directly onto another circuit board. The approach simplifies board-to-board soldering while maintaining strong electrical and mechanical connections.

From a design perspective, castellated holes offer several advantages. Their placement along the PCB edge makes solder joints easily accessible, improving solderability and inspection compared to pads located underneath a module. Edge-mounted half-holes also help ensure proper alignment during assembly, reducing the risk of placement errors. In addition, the exposed solder joints allow for straightforward post-assembly measurements using standard tools, which is not possible when connections are hidden beneath a module. Because castellated modules function as surface-mount sub-assemblies, they sit flush against the host PCB, minimizing gaps where dust or debris could accumulate.

Sierra Circuits supports customers through the complete castellated hole design process. During PCB layout, these features are defined as plated through-holes with their centers placed precisely on the board outline, ensuring consistent geometry after fabrication. Best practices, such as keeping components on one side of the module and reserving a clear area on the mating PCB, are incorporated to optimize manufacturability and assembly reliability.

Manufacturing PCBs with castellated holes requires specialized processes and close coordination between design and fabrication. Standard milling tools are not suitable, as the copper plating within the holes can damage conventional equipment. Sierra Circuits employs appropriate heavy-duty milling techniques to cleanly route the board edges, followed by careful inspection and deburring to ensure high-quality, solder-ready castellations.

By combining advanced design expertise with proven fabrication processes, Sierra Circuits enables customers to integrate castellated hole PCBs confidently into their products. These capabilities help streamline module installation, improve inspection efficiency, and support the development of compact, high-performance electronic systems.

Click here to learn more about PCBs with castellated holes from Sierra Circuits.